Background: The use of real time ultrasound (US) for insertion of central venous catheters is limited by various factors such as availability, space constraints, and perceived lack of need according to surveys including cardiovascular anesthesiologists. Methods: After the ethical committee approval and patient consent, 201 adult patients scheduled for elective cardiac surgery were randomized to undergo internal jugular vein (IJV) cannulation by either of the two methods: Landmark technique (control group), static US technique using the transthoracic echocardiography (TTE) probe (US group). The success rate, number of attempts, total cannulation time, and complication rate in the two groups were compared. Results: The overall success rate and the first attempt success rate were significantly higher in the control group than the US group (99% vs. 89.6%, P = 0.003 and 87.6% vs. 70.8%, P = 0.003, respectively). The total number of attempts to locate the IJV with the finder needle as well as the puncture needle was significantly lower in the control group than the US group (2.2 vs. 1.3, P = 0.001and 1.7 vs. 1.2, P = 0.021, respectively). The incidence of arterial puncture was higher in the US group than the control group (9.4% vs. 1.9%, P= 0.020). The total cannulation time was also higher in the US group (430 ± 320 s) than the control group (197 ± 116 s, P= 0.001). Conclusion: The landmark technique has a higher success rate, lower complication rate, and total cannulation time as compared with the static US technique using the TTE probe for IJV cannulation in adult cardiac surgical patients.

Although the advantages of ultrasound (US) for central venous cannulation (CVC) have been validated [1],[2],[3] and it has been suggested as the standard of care for internal jugular vein (IJV) cannulation,[4],[5],[6],[7] the availability of an US machine may not be a possibility in all the settings, especially the cardiothoracic operation theater. The transthoracic echocardiography (TTE) probe which is supplied with transesophageal echocardiography machine is more readily available in the cardiothoracic surgery operation theaters. Thus, it may be a feasible option for US-guided IJV cannulation but has not been studied previously. Therefore, we conducted a prospective, randomized controlled trial (RCT) comparing the use of the TTE probe-guided static US technique with the landmark technique for IJV cannulation.

Methods

After the approval of the Institutional Review Board Committee and obtaining informed consent, the study was carried out in 201 adult patients undergoing cardiac surgery. Patients undergoing bidirectional Glenn shunt, Fontan surgery, or emergency surgery and those with local site infection, coagulopathy, anatomical deformity (burns, neck swelling, and surgical scar) were excluded from the study. The patients were allocated to one of the following groups using computerized randomization: Control group: Patients in whom IJV was cannulated by the standard landmark technique, US group: Patients in whom IJV was cannulated by static US technique using the TTE probe.

Under all aseptic precautions, cannulations were performed using a 7.5 F triple lumen catheter after the induction of general anesthesia and endotracheal intubation. The patient was placed in a 10–20°. Trendelenburg position with head turned to the left side so as to cannulate the right IJV. All the cannulations were performed by senior residents under the supervision of a consultant anesthesiologist.

Control group

The IJV was located at the apex of the triangle formed by the clavicle and the two heads of the sternocleidomastoid muscle. The fingers of the left hand were used to palpate the two heads of the sternocleidomastoid, the carotid pulse, and the IJV. The IJV was first located with a 22-gauge finder needle attached to a 5 ml syringe held at an angle of 45° directed toward the ipsilateral nipple. After the successful location, the finder needle was withdrawn and the venous puncture was performed using an 18-gauge puncture needle. The catheterization was completed using the Seldinger technique.

Success was defined as the location of the IJV by the finder needle within five attempts. The first attempt success was defined as location of the IJV by finder needle in the first attempt. Time to CVC was defined as the time taken from the insertion of the finder needle till de-airing and flushing of all the three ports of the triple lumen catheter. The duration of US was defined as the time between the placements of the probe on the neck till the marking of the course of the vein on the skin. The number of attempts made by the finder needle and the puncture needle and complications (arterial puncture, hematoma, etc.), if any, were recorded. The complication rate was calculated as a percentage of the total number of complications with respect to the sample size. Total cannulation time in the US group was calculated by adding the duration of US to the CVC time.

Statistical analysis

A sample size of 200 patients was calculated to ensure a mean difference of one and standard deviation (SD) of 1.4 in a number of attempts yielding a power of study as 90% with a confidence interval (CI) of 95%. The statistical package SPSS 15.0 for windows (SPSS Inc., Chicago, IL, USA) was used for statistical analysis. The values were expressed as mean ± one SD or median with interquartile range. Qualitative data were analyzed by Chi-square test, and quantitative data were analyzed using Mann–Whitney test. A P ≤ 0.05 was considered statistically significant.

Results

Of the 201 patients, 105 were allocated to the control group, and 96 to the US group. The two groups were comparable (P > 0.05) for the demographic profile of the patients [Table 1] as well as for the type of surgical procedures performed [Table 2]. Mitral valve replacement was the most commonly performed surgery in both the groups. Visualization of IJV by US was easily possible in all the patients. The parameters related to IJV cannulation are depicted in [Table 3]. Success was achieved in 103 cases in the control group yielding a success rate of 99%; this was significantly higher (P = 0.003) than the US group (successful in 86 cases with a success rate of 89.6%). The likelihood of success was 12 times higher in the control group than the US group with an odd's ratio (OR) of 12.1 (95% CI: 1.5–96.3). The first attempt success rate was 87.6% (92 out of 105 cases) in control group, which was significantly higher (P = 0.003) than in the US group (70.8%, 68 out of 96 cases). The chance of the first attempt success was 3 times higher in the control group than the US group (OR = 2.9, 95% CI = 1.4–6.0). The total number of attempts with the finder needle was significantly less in the control group than the US group (mean 1.25 ± 0.8, 2.18 ± 2.4, respectively; median 1.00 [1–1], 1.00 [1–2], respectively; P = 0.001). The total number of attempts with the puncture needle was also significantly less (P = 0.02) in the control group (mean 1.21 ± 0.7, median 1.00 [1–1]) than the US group (mean 1.72 ± 1.8, median 1.00 [1–1]). Arterial puncture was the only complication reported in both the groups; it occurred in eleven patients in the study, of which two were in the control group (1.9%), and nine cases belonged to the US group (9.4%). Hence, the incidence of arterial puncture was significantly lower (P = 0.02) in the control group versus the US group. The likelihood of arterial puncture was 5 times lower in the control group than the US group (OR = 5.3, 95% CI = 1.1–25.3). Furthermore, the total cannulation time was significantly higher in the US group (control group = 197.3 ± 116.7 s, US group = 430.2 ± 320 s, P < 0.001).

According to this study, the landmark technique was superior to the static US-guided technique using the TTE probe with a higher success rate as well as the first attempt success rate and a lower complication rate.

The success with US depends on the type of US-guided technique (static vs. real time or dynamic), the type of US probe used as well as the nature of the study population. Most of the studies and meta-analyses which have demonstrated the superiority of the US technique over the landmark technique have used the dynamic method for US-guided IJV cannulation.[1],[2],[3],[8],[9],[10],[11],[12],[13],[14],[15] The dynamic method requires the US probe to be covered by a commercially available sterile sheath over which sterile gel is applied. The probe is held in the operator's left hand and placed over the anterior triangle of the neck to identify the IJV in short axis. The right hand is used to puncture the IJV with the needle, which can be seen entering into the vein as an echogenic line or reverberation. The static method was used in this study due to nonavailability of the sterile sheath in our institution. Few studies have compared the static method with the dynamic US method for IJV cannulation and have concluded that although the dynamic technique was better than the static technique with regard to the number of attempts, first attempt success rate, and CVC time; the complication rates were comparable.[16],[17] The possible explanation for the inferior results with the use of the static method is the displacement of the prepuncture skin mark due to movements of the patient head.[17] According to the revised guidelines for CVC insertion stated by the American College of Surgeons in 2010; real-time US rather than static US technique or the landmark technique is the safest, most cost-effective, and successful method of IJV cannulation.[5] Some authors have suggested that even prepuncture ultrasonic localization and visualization of the IJV is superior to the traditional landmark technique as it allows to visualize the course and diameter of the IJV along with its relation to the common carotid artery (degree of overlap), thus enabling to predict a difficult IJV cannulation.[4],[5],[16],[17],[18],[19],[20],[21]

Important to note is that varied definitions have been used for success rate, complication rate, and failure rates. Some trials have not defined placement failure. Few trials have defined success rate as the ability to insert IJV catheter irrespective of the number of attempts either with the original technique or with a rescue technique; some studies have not even defined the success rate. Hence, a lower overall success rate with the US technique (89.6%) in this current study could be attributed to the most stringent definition of a success rate (ability to aspirate blood with finder needle within five attempts). Furthermore, this study used a lower frequency probe (2–4 MHz) than the usually recommended higher frequency probe (more than 7 MHz).[18] The success rate with the static US technique was 82% by Milling et al.[16] The first attempt success rate using static US technique in our study was 70.8%, and this is in concurrence with other studies where the static US technique was studied (35–87%).[17],[19],[20],[21],[22],[23]

Among the 20 RCTs, which formed the basis for NICE guidelines, only four were performed on cardiac surgical population.[6],[24],[25],[26],[27] Two of these trials were performed using a Doppler-guided needle in the US group, of these Gratz et al. reported a higher first attempt success rate and a lower total number of attempts in the US group; whereas Vucevic et al. found that there was no significant difference in the total number of attempts for cannulation, complication rates, and time to CVC.[24],[25] Troianos et al. found a significantly higher first attempt success rate, lower incidence of arterial puncture, and CVC time with the US technique, but the overall successful cannulations were comparable in both groups.[26] Sulek et al. reported 50% reduction in the complication rate with the use of US rather than the landmark technique.[27] Even in three of the above-mentioned trials, where the US technique offers some advantage, the study populations did not exclusively comprise the cardiac surgical patients and also included patients undergoing thoracic, vascular, and abdominal surgeries.[25],[26],[27] Hence, the superiority of US for CVC in adult cardiac surgical patients has not been strongly established. Espinet and Dunning commented that there was no anesthesiologist involved in the NICE guideline group and as per them, there is no evidence to support the use of US for IJV cannulation in the adult cardiac surgical population, especially when no difficulty is predicted.[28] This study was also conducted exclusively in the adult cardiac surgical patients; these patients have fuller veins which were also easily visible on the surface and hence easy to puncture even with the landmark technique. In a similar study performed by the authors in pediatric patients undergoing cardiac surgery, the success rate was not improved by the use of US.[29] Detecting venous pulsation with respiration was a good predictor of easy CVC placement although this was visible only in 78.3% patients in one study which also concluded that prepuncture US is not routinely needed when respiratory jugular venodilation can be used as a landmark to puncture.[23]

A survey of predominantly cardiovascular anesthesiologists revealed that although dedicated vascular US machines are now commonplace, they are not routinely used in the cardiovascular operating room.[30] Some other recent surveys (not among cardiac operating rooms) have revealed similar results.[31],[32] The important reasons cited for the poor usage of the US are a lack of resources and training or experience, and even a belief that US is not necessary for safe and effective insertion of central venous catheter.[30],[32] Furthermore, the belief that traditional landmark technique will still be required in clinical settings when US is not available is another major reason for failure to adopt US for central venous catheterization.[33],[34] Additional concerns over increased procedure time, and the need for additional equipment in an already crowded space may limit the use of US, despite known advantages. The intraoperative use of TEE during cardiac surgery is common. The machines are usually supplied with a surface probe for TTE. The TTE probe can conveniently be used for localizing and assisting cannulation of the IJV.

The inferior results observed in the US group in this study may be related to the involvement of two personnel in the US group versus one person in the control group. The insertion of the needle at a site directed by someone else may have contributed to the difference. Further, the direction of the needle to the lower marked point may have contributed, at least in part to the higher arterial puncture rate in the US group.

It is understandable that when a new technology is available, it is eventually likely to find a place in the clinical practice. However, optimum utilization of technology needs to be determined. This study has shown that the US does not offer any advantage over the conventional landmark technique in adult cardiac surgical patients. It appears therefore that the use of US may be restricted for training, and screening before the landmark technique in this group of patients.

Conclusion

The use of a static US technique using the TTE probe for IJV cannulation does not improve the success rate or decrease the CVC time and complication rate when compared with the traditional landmark technique in the adult cardiac surgical population.

American College of Surgeons. [ST-60] Revised Statement on Recommendations for Use of Real-time Ultrasound Guidance for Placement of Central Venous Catheters. Chicago: ACS Committee on Perioperative Care; 2011. Available from: http://www.facs.org/fellows_info/statements/st-60.html. [Last accessed on 2014 Aug 31].